Hindered phenolic phosphite esters

ABSTRACT

This invention relates to new hindered phenolic phosphite ester compounds and their use as stabilizers in rubber compositions.

Unite States Patent Spacht Aug. 5, 1975 1 HINDERED PHENOLIC Pl-lOSPHITE ESTERS [56] References Cited [75] Inventor: Ronald B. Spacht, Hudson, Ohio UNITED STATES ATENTS t 3,112,286 11/1963 Morris et a1. 260/953 X [73] Assgnee' E z: 3,297,631 1/1967 Bown et a1..... 260/953 x many, 3,510,507 5/1970 Bown CI 9.1 260/953 x [22] Filed: Nov. 27, 1970 Primary ExaminerAnton H. Sutto [21] Appl' 93513 Attorney, Agent, or FirmF. W. Brunner; J. M.

Related US. Application Data Wallace [60] Division of Ser. No. 758,583, Sept. 8, 1968. Pat. No.

3,567,683, which is a continuation-impart of Ser. No. [57] ABSTRACT 381525 July 1964 abandoned This invention relates to new hindered phenolic phosphite ester compounds and their use as stabilizers in [52] US. Cl. 260/953; 260/973; 260/976 rubber compositions. [51] Int. Cl. C07F 9/12; CO7F 9/14 [58] Field of Search 260/953 I 4 Claims, N9 Drawmgs HINDERED PHENOLIC PHOSPHITE ESTERS This is a divisional application of copending application Ser, No. 758.583, filed Sept. 9, l968 now US, Pat. No, 3,567,683, which was a continuation-in-part of application Ser. No. 381,525, filed July 9. 1964, now abandoned.

This invention relates to new compositions of matter and is particularly concerned with phosphite esters of polyphcnols.

According to the present invention new compounds have been prepared which are phosphite esters of polyphenols. The polyphenols contain a ring substituent which has more than one carbon atom and may be prepared by condensing the phenol with an unsaturated hydrocarbon.

The new compositions can be structurally represented by the following formula:

in which R is a hydrocarbon radical containing from 4 to carbon atoms, P represents the phosphorus atom, and y is selected from O, l and 2, z is selected from 1, 2 and 3, the sum of y and z equals 3 and A is selected from the group consisting of and wherein R and R" are selected from the group consisting of the same and different tertiary alkyl radicals containing from 4 to 9 carbon atoms, R is selected from hydrogen and alkyl radicals containing from 1 to 10 carbon atoms and X is a divalent radical selected from the group consisting of S O and saturated aliphatic radicals containing from 1 to 10 carbon atoms.

These products are prepared by reacting a phosphorus chloride having the formula in which R is a hydrocarbon radical containing from 4 to 10 carbon atoms, P represents the phosphorus atom, "is selected from 0, l and 2 and z is selected from 1, 2 and 3 and the sum of y and 1 equals 3 with a phenol selected from the group consisting of phenols having the formula:

RI (I) HO Q OH X ([T) HO OH R|YI q" and (TII) R wherein R and R are selected from the group consisting of the same and different tertiary alkyl radicals containing from 4 to 9 carbon atoms, R is selected from aliphatic radicals containing from 1 to carbon atoms, the materials beingreacted in the ratio of Z mols of the phenol to '1 mol of the phosphorus compound. 4

Illustrations of radicals represented by the symbolsv are, for example, where R represents hydrocarbon radi-.

cals containing from 4 to 10 carbon atoms R can be. radicals such. as the various butyl, pentyl, hexyl, heptyl,

octyl, nonyl and decyl radicals and benzyl and phenethyl radicals; where R" and R" represent tertiary alkyl radicals they may be radicals such as tertiary, butyl, tertiary amyl, tertiary hexyl, tertiary heptyl, tertiary octyl, and tertiary nonyl; where X represents divalent aliphatic radicals containing from 1 to 10 carbon atoms the radicals can be methylene, ethylene, propylene, the butylene and isobutylidene radicals, amylene, hexyland the purified materials are useful as stabilizers for organic materials subject to degradation on exposure to air or oxygen and are particularly usefulas stabilizers ene, heptylene, octylene, nonylene and decylene radi- 2O cals; and whereR represents alkyl radicals containing from 1 to 10 carbon atoms the radicals can be methyl. ethyl; n-propyl, isopropyl, the various isomeric butyl, pentyl. hexyl; heptyl, octyl, nonyl and decyl radi- Illustrations of phenols of formula ll where X is are 2,2-thio bis(4-methyl-6 tertiary butyl phenol); 4,4-thio bis(3-methyl-6 tertiary butyl phenol); and 4,4-thi0 bis(2,5 tertiary butyl phenol). Where .X is

I cals.

O the phenols of formula ll can be 2,2'-oxy bis(4 methyl 6 tertiary butyl phenol); 4,4-0xy bis(3-methyl- 6 tertiary butyl phenol); and 4.4-oxy bis(2.6 tertiary 'butyl phenol).

Representative compounds illustrating the above forfor polymeric materials such as polyester resins and rubbers of various kinds,includin'gnatural rubber and the synthetic rubbers, especially .cis-l ,4 polyisoprene polybutadiene, 'pol'ychloroprene and copolymer rubberssuch as butyl rubber; the. rubbery butadienestyrene copolymers, and the rubbery copolymers of butadiene and acrylon'itrile. I

In the practice of the invention the phosphiteesters of phenolshaving desiredcharacteristics can be obtained' by reacting phosphorus trichloride. with a selected alkyl ated phenol and then reacting the product with the proper hindered phenol. The preparation of the compounds is illustrated by the following examples.

EXAMPLE 1 Two hundred and four grams of styrenated phenol (88 percent monoalpha phenylethyl phenol and 12 percent di (alpha phenyl ethyl) phenol) and 412 grams of PCl were mixed at room temperature and then slowly heated under reflux until no moreHCl came off (about 4 hours). The excess PClg, was removed byheating the mixture to a pot temperature of 175 C. at 25 millimeters of mercury pressure. The mono (alpha phenylethyl phenoxy) phosphorus dichloride obtained weighed 288 grams. This productwas reacted with various phenols. The data. onthese reactions is tabulated mula would have substituents as follows: below.

R A R R" R X Y Z Y Z Butyl l tbutyl l 2 2 l Butyl ll t-butyl t-butyl methylene l 2 2 l Amyl ll t-butyl t-butyl methylene l 2 2 l Hexyl 7 ll t-butyl t-butyl methylene l 2 2 l Octyl Il t-amyl l-amyl ethylene l 2 2 l Octyl ll t-amyl t-amyl propylene 1 2 2 l Nonyl ll t-hexyl t-hcxyl butylidenel 2 2 l Decyl ll toctyl t-octyl isobutylidene l 2 2 l Butyl lll t-hutyl methyl l v 2 2 I ll! t-butyl methyl 0 3 Grams of Example Product of Phosphorus No. Example 1 Phenolic Compound Product Found Theory 2 50.8 2.5 ditertiary butyl l26grams light brown 3.82 4.21

- hydroquinone 83.5 grams sticky resin i 3 71.0 Reaction product of nonyl 212 grams light yellow 2.78 3.40

phenol and HCHO 157 grams soft resin 4 30.5 2.2-methylene bis(4-methyl- 92 grams brown sticky 2.69 3.37 6-tertiary butyl phenol) resin 68.4 grams 5 30.5 Butylatcd reaction product of 159 grams brown resin' 1.73 L95 pcresol and dicyclopentadiene 136 grams The crude reaction mixture can be purified by washing with waterand drying the material, preferably under vacuum, to remove water and other volatile substancesQThe products of the invention are customarily a resins which vary from sticky resinous materials to soft I resins to dry flaky materials. They are light colored and vary from light yellow to brown-in color. The characteristics of the materials can be; controlled by proper selection of thephenolicreactant. Both the unpurified unreacted nonyl phenol. A residue of 181 grams remained.

The butylated reaction product of p-cresol and dicyclopentadiene used in Example 5 was prepared as follows:

Three hundred and thirty grams of para-cresol and 9.0 grams of a phenol BF complex containing 26 percent BF were heated to 100 C. and then 132 grams of dicyclopentadiene were added over a period of 3 /2 hours. The excess para-cresol was removed by heating to a column temperature of 150 C. at 4 millimeters, this procedure also removed the BF;; catalyst. A residue of 316 grams was obtained.

Two hundred and thirty-six grams of this product were dissolved in an equal weight of toluene and 4.0 grams of H 50 added. The solution was heated to 80 C. and 168 grams of isobutene added over a period of 1% hours. The mixture was heated 1 hour longer, then the catalyst was destroyed with a Na CO solution. Volatiles and unreacted materials were removed by heating to 175 C. at 30 millimeters. Catalyst residues were removed by filtration. Weight of the product was 313 grams.

EXAMPLE 6 One hundred and thirty-six grams of a butylated reaction product of para-cresol and dicyclopentadiene prepared as above were dissolved in 200 milliliters of toluene and warmed to 70 C. Then 32.2 grams of mono (tertiary nonyl phenoxy) phosphorus dichloride were added. The mixture was 'heated to a temperature of from 70 to 80 C. for 3 hours after all of the phosphorus compound had been added. Then the mixture was heated to 180 C. at millimeters of mercury pressure to remove volatile materials. The product obtained as a residue weighed 157 grams. It was a brown resin. On analysis the percent phosphorus found in the product was 1.87. The percent phosphorus according to theory is 1.92.

EXAMPLE 7 One hundred and seventy-nine grams of a butylated reaction product of pcresol and dicyclopentadiene were dissolved in 200 milliliters of toluene and then 12.5 grams of PCL, added slowly at 60 C. Nitrogen gas was bubbled through the mixture to remove the last traces of HCl. Finally the mixture was heated to 190 C. at 200 millimeters of mercury pressure to remove the toluene. The product obtained was a dark brittle resin.

EXAMPLE 8 Two hundred grams of 2,5 ditertiary amyl hydroquinone were placed in a glass flask that'was equipped with a stirrer, a dropping funnel and a reflux condenser EXAMPLE 9 Fifty-three and one-half grams of mono (tertiary nonyl phenoxy) phosphorus dichloride were added to a slurry of 2,5 ditertiary amyl hydroquinone in 200 milliliters of toluene at C. The mixture was refluxed for 2 hours after all of the phosphorus compound had been added. Then the excess ditertiary amyl hydroquinone was removed by heating the mixture to 235 C. (pot temperature) at 8 millimeters of mercury pressure. The

product obtained weighed 122 grams.

7 EXAMPLE l0 Sixty-eight grams of 2,2 methylene bis(4-methyl-6- tertiary butyl phenol) were dissolved in 200 milliliters of toluene and heated to 70 C. Thirty two grams of mono (tertiary nonyl phenoxy) phosphorus dichloride were then added. The mixture was heated for 4 hours. Then toluene and other volatile materials were removed by heating the mixture to a pot temperature of C. at 15 millimeters of mercury pressure. The residue weighed 88.0 grams. The product was a soft brown resin. On analysis the percent phosphorus found in the product was 3.42. The precent phosphorus according to theory is 3.32. i

The materials of the invention which are most preferred for use as stabilizers for rubber are the ones derived from the reaction products of a phenol and dicyclopentadiene and a phosphorus chloride. Of these the alkylated derivatives, especially the butylatcd products, are particularly preferred. The following examples show the effectiveness of these materials as antioxidants in a rubber stock. In these tests the antioxidants were incorporated in the following standard recipe for testing:

Extracted Pale Crepe 100.00 Zinc Oxide 5.00 Sulfur 3.00 Stearic Acid 1.50 Antioxidant l .00 Hcxamcthylenetetramine 1 1.00

The following table shows the results obtained when cured rubber samples were tested in the oxygen bomb test:

TABLE (Cure 50 Minutes at 285 F.)

I 7r Tensile TABLE Continued (Cure so Minutes at 285 F.

* Aged 72 hours at 70 C. under 300 lbs. per square inch O pressure the antioxidant used is the reaction product of butylated phenol sulfide and tertiary nonyl pl'lcnoxy phosphorous dichloride the antioxidant used is the reaction product of butylated m-p cresol sulfide and tertiary nonyl phenoxy phosphorous dichloride.

The followingtable shows further results obtained when cured rubber samples were tested after 72 hours 15 exposure in the oxygen bomb test at 70 C.

Age-Rite Geltrol** Ex. X Ex. IV

Antioxidant Cure 7 in Minutes 70 9O 70 90 70 90 Original Tensile (psi 2050 2900 2045 2180 2245 2235 Final Tcnsilc(psi)* (after 72 hrs. in oxygen bomb) O 0 I955 2040 l730 1900 9? Tensile Retention 0 0 95.7 93.7 77.1 85.2

" psi pounds per square inch compound sold by Goodrich which can he represented by the formula:

H CH

The products of the invention are useful as stabilizers for rubber. They may be incorporated-in the rubber in solution, or added to rubber, coagulated rubber or rubber latex, or mixed with rubber in masticating machines such as mills and Banbury mixing machines. The amounts used are relatively small. The amount used will be from 0.25 to 5.0 percent by weight based on the weight of the rubber and preferably from 0.5 to 2 percent by weight based on the weight of the rubber.

The following table shows the results obtained where the rubber samples were SBR-1006. The oxygen absorption was compared to alkylated hindered phenol and commercial phosphite.

Description of Stabilizer 7: O Absorbed at The data clearly show the superior stabilizing effect of the stabilizers from Examples 2, 3, 4, 5, 6, Sand 10'.

The oxygen absorption tests were conducted by dissolving in benzene portions of an unstabilized SBR polymer (1006). The benzene contained the antioxidant to be tested at a' level of 1.00 part of antioxidant per 100 parts of SBR polymer. The cements so formed were poured onto aluminum foil so as to form a thin film. After drying the weight of rubber was obtained in connection with each sample. Thereafter the foil with the adhering rubber strip was placed in the oxygen absorption apparatus. The time required for each sample to absorb 1.0 percent oxygen was determined. This testing procedure is described in further detail in Industrial and Engineering Chemistry, 43, p. 456 1951 and Industrial and Engineering Chemistry 45, p. 392 1953).

While certain representative embodiments and details have been shows for the purpose of illustrating the invention it will be apparent to those skilled in this art that various changes and modifications may be made therein without departing from the spirit or scope of the invention.

I claim:

1. A product corresponding to the formula 9 10 2. A product corresponding to the formula in which is l and y is 2 and 2 mols of a phenol of the formula R O j V l l l 5 O CH CH CH C I 3 4. The product prepared by reacting 1 mol of PCL;

3 2 X C CH CH with 3 mols of a phenol of the formula 2 3 3 c11 0H 0H 0H r a 2 o in which R is a hydrocarbon radical containing four to 15 CH 3 10 carbon atoms selected from the group consisting of butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, benzyl and phenethyl radicals. OH CH3 3. The product prepared by reacting 1 mol of a phosl phorus compound having the formula C H UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,898,30 -r DATED August 5, 1975 rNVENTOR(S) 1 Ronald B. Spachc It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7 Table, Unaged Data" should be --Aged Data--.

Signed and Scalcd this I Third Day Of July 1979 [SEAL] Attest:

LUTRELLE F. PARKER Anestulg Oflicer Acting Commissioner of Patents and Trademarks 

1. A PRODUCT CORRESPONDING TO THE FORMULA
 2. A PRODUCT CORRESPONDING TO THE FORMULA
 3. THE PRODUCT PREPARED BY REACTING 1 MOL OF A PHOSPHORUS COMPOUND HAVING THE FORMULA
 4. THE PRODUCT PREPARED BY REACTING 1 MOL OF PCI3 WITH 3 MOLS OF A PHENOL OF FORMUL 